The European legal systems now recognize that an electronic document of which the author can be identified with certainty and which is conserved in conditions that make it possible to ensure the integrity thereof has the same probative value as writing on a paper medium (Article 1316 and following of the French Civil Code, for example). However, the most widespread production systems, such as a word processor generating a document in PDF (Portable Digital File) format and an interchange system (electronic messaging on the Internet) for interchanging electronic documents, do not currently make it possible to guarantee either the identity of their author or their integrity. The problem relates both to private correspondence between individuals or between an individual and an enterprise or an institution and correspondence between enterprises and authorities or between an enterprise or an authority and its clients or its users. In the latter case, the flow of documents may be particularly large (several tens of millions of invoices per month are sent to the clients of EDF, of GDF Suez, of Orange). The manufacture and transmittal of these documents are therefore automated in production systems which necessarily involve many operators. If it is desired to guarantee that the document sent and archived is identical to that originally produced, it is therefore necessary to ensure end-to-end traceability of all these operations and a verification that the operators have carried out the operations that they had to execute. This applies to a system for production of paper documents or of electronic documents. Moreover, with electronic transmittal, for the documents thus sent to be considered to be validly addressed, it is necessary both that these documents bear the identification of the sender and that the latter is assured of the identity of the intended recipients.
Partial solutions have been provided for the problem of the probative value of electronic documents interchanged electronically. In particular, if the sender has an electronic signature certificate delivered under prescribed conditions and of which the validity is verified by a certification authority, his identity as the author of an electronic document on which he has placed the said certificate will be recognized as validly demonstrated. But electronic signature certificates are still not very widely used notably because of their high cost and of their awkwardness of use. Moreover, this does not solve the problem posed by a document production system involving multiple operators. The applicant has already filed patent applications in France with the objective notably of supplying a score of the identity of a sender and of recipients of electronic documents that makes it possible to assess the probative value of the documents interchanged between these parties. See for example the applications filed under numbers FR/06 04 107 and FR/08 02 239.